package cz.uhk.max.filters;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class SessionFilter implements Filter {

	public void init(FilterConfig config) throws ServletException {
	}

	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		
		HttpServletRequest httpRequest = (HttpServletRequest) request;
		HttpServletResponse httpResponse = (HttpServletResponse) response;
		HttpSession session = httpRequest.getSession(); 
		
		String contextPath = httpRequest.getContextPath();

		if (session == null) {
			httpResponse.sendRedirect(contextPath + "/error.jsf?sessionExpired=true");
		} else {
			httpResponse.setHeader("Cache-Control", "no-cache");
			httpResponse.setHeader("Pragma", "no-cache");
			httpResponse.setHeader("Expires", "1.1.1900");
			chain.doFilter(request, response);
		}
	}

	public void destroy() {
	}

}
